Projects – Page 3 – WB3GCK QRP Amateur Radio

Dollar Store Special

[NOTE: This is an updated version of an old article from my QSL.NET website. In the interest of full disclosure: My local dollar store no longer sells the speaker wire I used. While it’ll probably cost you a few more bucks to build one, it’ll still be a cheap antenna. Although the original article has been on my website for 15 years, I still get the occasional email from folks who have built one.]

I love rummaging through our local dollar store. One of the biggest bargains in our local dollar store is speaker wire. You can get 50 feet of two-conductor speaker wire for a buck. Not too shabby. I always keep a bunch of the stuff on hand for antenna experimentation.

Diagram of the Dollar Store Special. See the text for other counterpoise options. — Diagram of the Dollar Store Special. See the text for other counterpoise/radial options.

Using a single 50-foot roll of dollar store speaker wire, I made a simple 50-foot random wire antenna with counterpoise wires to cover the 40, 30 and 20-meter bands. I stashed the whole kit in a zip-lock sandwich bag and always keep it on hand as a backup antenna system whenever I operate in the field. With a simple antenna tuner of some sort, this will get you on the air in a pinch, should your primary antenna fail.

This is the 20 AWG speaker wire I used. Sadly, my local dollar store no longer carries it. I wish I had bought a ton of it while it was available. — This is the 20 AWG speaker wire I used. Sadly, my local dollar store no longer carries it. I wish I had stocked up while it was available.

Here’s all you have to do:

Separate the conductors so that you now have two separate 50-foot wires.
For the radiator, take one of the 50-foot wires and crimp a small ring lug to one end—right over the insulation. This gives you someplace to tie a line to hoist it up. On the other end, just strip off a half-inch or so of the insulation. You can leave it bare or add whatever kind of connector you want; whatever works best with your tuner.
For the counterpoise wires, take the remaining 50-foot wire and cut it so that you have a 33-foot wire and a 17-foot wire. If you only want to work 40 and 20 meters, you can stop right here. You now have counterpoise wires for both of these bands.
To provide a counterpoise wire for 30 meters, take the 33-foot wire from Step #3 and cut it so that you now have a 23-foot wire and a 10-foot wire. Strip off about 1/2-inch of insulation from one end of the 23-foot wire. Install a quick-disconnect connector of some sort on the other end, so that you can join the 23-foot and 10-foot wire sections together. The idea here is that, with the two wires connected, you have a 33-foot counterpoise wire for 40 meters. With the two sections separated, you now have a 23-foot counterpoise wire for 30 meters.

I used a ring terminal to terminate the 50-foot wire. Note that the terminal is crimped over the wire's insulation. The metal ring terminal is electrically-isolated from the antenna wire. — I used a ring terminal to terminate the 50-foot wire. Note that the terminal is crimped over the wire’s insulation. The metal ring terminal is electrically-isolated from the antenna wire.

This is the quick-disconnect connector I used on the original version of the counterpoise wire. I used some Goop® adhesive to provide some strain relief.

[Note: If you only plan to operate with the radials laying on the ground, cutting them to resonance isn’t too important. You can simplify things a bit by going with just the 33 and 16-foot wires. I think two 25-foot wires would be sufficient, as well. Three 16.6-ft radials is another option to consider. Feel free to experiment here and see what works for you.]

In operation, just hoist one end of the 50-foot radiator up in a tree or other suitable support. Connect the other end to the hot side of your tuner. Connect the 33-foot and 17-foot counterpoise wires to the ground connection on your tuner and lay them out on the ground. When you want to work 30 meters, just disconnect the quick-disconnect on the longer counterpoise wire. Pretty simple, eh? Any type of simple L-tuner should work fine for this.

Please note that I wouldn’t recommend using this wire for a permanent outdoor antenna. It’s not suited for that kind of use. But for temporary outdoor use, it’ll do just fine. Besides, if the wire goes bad, you can always replace the whole thing for a dollar!

73, Craig WB3GCK

Portable Antenna Ground Mount

Here’s yet another quick little hack. I raided my junk box to cobble together a ground mount for my portable vertical. While this solved a couple of specific issues I had, it might only be of interest to a few of you folks out there.

I often support my 19-foot vertical with one of those inexpensive fishing poles from eBay. (I paid around $10 USD for my 7.2M pole.) I had been using a simple method for ground mounting. I shove a screwdriver in the ground, take the bottom cap off of the pole, and place the pole over the screwdriver. Voila!

While the screwdriver technique is a useful way to support my vertical, there are two issues with it. First, the screwdriver method places the bottom of the pole in direct contact with the dirt. This can gunk up the threads on the bottom of the pole. (Ask me how I know.) Next, since my homebrew 19-foot vertical takes up the entire length of the pole, the matchbox ends up too close to the ground for my liking. I made a simple little gizmo that addresses both of these issues.

Antenna ground mount in use with my 19-foot vertical

From some scraps and junk I had on hand, I used the following:

5 inches of 1/2-inch PVC pipe
Approx 6 inches of 3/4-inch PVC pipe
3/4″ x 1/2″ PVC reducer
(2) 3/4″ PVC end caps (with flat ends)
Stainless steel toilet float rod (1/4″ diameter x 10″ long. 1/4-20 threads on each end of the rod)
(2) 1/4-20 nuts
1/4″ lock washer
Duct tape (optional, for a better fit between the 1/2-inch PVC and the bottom of the pole)
A dab of Lock-Tite thread locker

[Note: The PVC pipe I used works with the particular pole I use. If the bottom of your pole has a different inside diameter, you might need to use a different size pipe.]

I joined the two pieces of PVC pipe together with the PVC reducer. Then I glued the two end caps together, back-to-back. Next, I drilled a 1/4-inch hole through the center of the two end caps. I fastened the stainless steel rod with two nuts and a lock washer. I also used a dab of thread locker for good measure. I had to do some sanding on the 3/4-inch pipe to allow the end caps to slide on and off easier. At this point, you might want to put a layer or two of duct tape on the 1/2-inch pipe for a snug fit inside the pole.

The two main assemblies of the antenna ground mount

Stainless steel rod bolted through the two back-to-back PVC end caps

In the field, I place the end cap assembly on the 3/4-inch pipe and shove the rod into the ground. The pole goes over the 1/2-inch PVC pipe, of course. This places the bottom of the pole about 8 inches above the ground. With lightweight poles, guying is unnecessary. For travel, I flip the end cap assembly around so that the bolt stores inside the pipe. This prevents poking holes in my backpack or bicycle pannier bags.

Antenna ground mount configured for travel. The stainless steel rod is stored safely inside the PVC pipe assembly.

The threads on the end of the stainless steel rod pick up some dirt in use. It’s not a major problem but I might cut the rod off just above the threads. I haven’t decided yet.

That’s all there is to it. I’m hoping the accompanying pictures clarify how I built it.

72, Craig WB3GCK

Adjustable Bungee Cable Ties

This is another one of those little hacks that takes longer to describe than to build. Some time ago, I stumbled on a clever idea online that has been useful in my ham radio activities.

I used to use ball bungee fasteners in a variety of sizes as temporary fasteners. While they are handy, they have limitations for my uses. On occasion, I found that the sizes I had available were either too small or too large for the task at hand.

A year or two back, I found a great video on the MOD YouTube Channel. The video described how to make these simple, adjustable cable ties. I made up a few and found them handy for several ham-related applications.

A completed bungee cable tie, along with one of the two-hole cord locks I used.

These little devices have a multitude of uses but my main use is for antennas in the field. I use them to fasten a BALUN or UNUN to a telescopic pole for portable verticals.

I also found they are also handy for lashing odd items to the MOLLE loops on my backpack. In a recent post, I showed how I use them to secure a 19-foot telescopic pole to my sling pack.

I use one of the bungee ties to attach the 19-foot vertical matching box to the fiberglass pole. — I use one of the bungee ties to attach my 19-foot vertical matching box to the fiberglass pole.

Of course, they make great cable ties. Their ability to adjust allows them to fit a wide variety of cables.

You only need 2 things to make these: some shock cord and some double hole cord locks. (If you watched the MOD video, you already know all this.)

I use 4mm diameter shock cord most often to make these. For some smaller, light-duty applications, I have used a thinner 2.5mm shock cord. I have found that the cord locks seem to hold better with the larger 4mm shock cord.

Construction is super simple.

Cut the shock cord to the desired length. Be sure to singe the cut ends with a lighter to prevent fraying.
Put the two ends through the holes in the cord lock.
Holding the two ends together, tie a simple overhand knot and snug it down.
To use them, place the bungee around whatever you need to fasten. Place the loop end over the cord lock to hold it. Press the button on the cord lock and pull the ends to cinch it down.

That’s all there is to it. In the time it took to write and edit this post, I could have made a ton of these things. It’s not an Earth-shattering thing but sometimes it doesn’t take much to amuse me.

Thanks to MOD YouTube Channel for sharing this great idea.

72, Craig WB3GCK

[Disclaimer: I have no financial interest whatsoever in Amazon or any of these products.]

Links:

Revisiting the Rybakov 806 Vertical

Some recent Internet discussion got me thinking about the Rybakov 806 Vertical antenna. This easy-to-build antenna has served me well over the years. So, I went back and revisited some of the ways I’ve used it.

What the heck is a Rybakov anyway?

The Rybakov 806 Vertical appears to be the brainchild of Enrico IV3SBE from Italy (now 5Z4ES in Kenya). The term, Rybakov, is Russian for “fisherman.” That’s right… It’s an antenna with a Russian name designed by an Italian who lives in Africa — truly an international creation. From what I could glean from exhaustive Internet searches, this design dates back to the mid to late 2000s. I found numerous references to it from 2009.

The classic Rybakov configuration is a 7.6m or 8m (~25 or 26 feet) wire fed through a 4:1 UNUN. The length isn’t critical, as long as you avoid resonance on the bands of interest. It’s often supported by a telescopic fishing pole (hence, the name, “Rybakov”). Being a non-resonant antenna, you need to use an antenna tuner to make it work. You also need to use radials or some other type of ground.

The antenna can cover 80M through 6M (the “806” part of its name, I suppose). The band coverage depends on the wire length used and the capabilities of your tuner. With a 7.6M wire, you can cover 40M and up without problems. For 80M coverage, plan on using a longer radiator.

The only thing you need to build is the 4:1 UNUN. The IW7EHC website provides detailed instructions for building one. Beyond that, you just need to cut some wire to length for the radiator and radials. Easy peasy!

My experience with the Rybakov

I had been using this type of antenna before I even knew it had a name. Rick KC8AON had a version of this type of antenna he called, “The Untenna.” That’s where I found it.

My first experiment with it was in a “stationary mobile” setup. I rigged up a 26-foot vertical wire and grounded the UNUN to the body of my truck. My Z-817 tuner was able to load it up with no difficulty. I had no problem making contacts and I liked the multi-band coverage.

I next used the Rybakov at a Boschveldt QRP Club Field Day. I set up a 26-foot ground-mounted vertical and used about six 16-foot radials with it. Again, the performance seemed decent and I remember doing well on 10M that year. The only shortcoming was that it wouldn’t load up on 80M.

The next year, I solved the 80M problem by using a 50-foot wire in an inverted L configuration. For the ground, I used six 16-foot radials and two 33-foot radials. This configuration gave me full coverage from 80M to 10M and it worked great. This antenna configuration became my “go to” Field Day for several years. In later years, I used a 53-foot radiator re-purposed from another antenna project.

My typical implementation of the Rybakov 806 antenna. A length of 25 to 27 feet does well from 40M and up. I go with a 53-foot radiator for 80M coverage. — My typical implementation of the Rybakov 806 antenna. A length of 25 to 27 feet does well from 40M and up. I go with a 50 or 53-foot radiator for 80M coverage.

I used another version of the Rybakov with the pop-up camper that I used to own. I strapped a 31-foot Jackite pole to the camper and used it to support a 27-foot wire. I grounded the UNUN to the body of the camper. This antenna worked great on 40M to 6M and, best of all, I didn’t need to go outside at night to change bands. I used this antenna with good results for several years until I sold the camper.

I also built a Rybakov that I use as a backup antenna in the field. I built a small 4:1 UNUN that I use with a 25-foot radiator and a 25-foot radial. The antenna, along with a short length of coax, is easy to carry in my pack.

The bottom line (for me, at least)

I’ve had good luck with the Rybakov Vertical over the years. Is it the best antenna? Nope. Purists will argue about UNUN, ground, and coax mismatch losses. Yep, there are those. Yet, its simplicity and “no gap” band coverage are hard to beat. It’s easy to deploy in the field and it really does work.

If you’re in the market for a simple portable antenna project, the Rybakov 806 is an easy one.

[Update 4/3/2019: I’ve always wondered about the rationale behind the 25-foot radiator often used with the Rybakov antenna. An article in QST [1] by Joe Reisert W1JR shed some light on that for me. Joe’s article discusses the 3/8-wave vertical antenna. According to the article, the 3/8-wave antenna has a low take-off angle and its 200-ohm feedpoint is easily matched with a 4:1 transformer. Its higher radiation impedance provides good performance with just four 1/4-wave radials. For 20M, a 3/8-wave radiator is about 25-ft. Similarly, for 40M, it would be 50-feet. So, my guess is that’s the concept behind the Rybakov design.]

73, Craig WB3GCK

Reference Links:

Reference Articles:

Reisert, Joe W1JR, “The 3/8-Wavelength Vertical — A Hidden Gem,” QST, April 2019, pp. 44-47.

FT-817 Power Connection

I’ve seen a lot of discussion on the Internet lately about the FT-817’s less-than-robust DC power connector. Its miniature coaxial power connector has long been recognized as a failure waiting to happen. I thought I’d chime in with my crude, little hack.

Over the years, users have come up with a variety of ways of dealing with the FT-817’s power connector. If you’re brave enough, you can just hard-wire the power cord directly to the FT-817’s main circuit board and eliminate the connector altogether. You can also buy a really slick adapter that gives you an Anderson Powerpole connector on your FT-817.

When I bought my FT-817 almost 15 years ago, I was immediately leary of the little 4.0 x 1.7 mm power connector; there was no way it was going to hold up in the field. I didn’t know of any commercial options at the time, so I raided my junk box to come up with a solution, albeit a crude one.

The power cord with an Anderson Powerpole connector attached to my FT-817

I merely attached a small right angle lug to the FT-817’s ground screw. Then, I used a couple of small nylon cable ties to secure the power cable to the lug and provide some strain relief. I installed Powerpole connectors on the other end of the cable. It’s not pretty but it served the purpose.

Close-up of the right-angle lug attached to the ground stud. Two small nylon tie-wraps secure the power cord to the lug. An unused lug is shown in the bottom of the picture.

Although my FT-817 doesn’t see as much field use as it used to, my stupid-simple hack is still going strong after 15 years. While this approach doesn’t eliminate the FT-817’s little DC connector, it has (so far) survived many years of portable use in the field.

72, Craig WB3GCK

Connecting Two Keys to the KX3

When operating in the field, I often like to alternate between a straight key for SKCC contacts and paddles for everything else. I found a quick and easy way to do this, courtesy of an excellent article by Rich AG6QR.

In the past, I would sometimes run an external keyer and connect a straight key in parallel with the keyer’s output. I have often used this as a way to use both computer keying and paddles during Field Day. I have also resorted to putting the CW KEY1 jack into the straight key mode and turning my Palm Mini paddles on their side to simulate a straight key. I could have used the Elecraft paddles designed for the KX3 but that arrangement isn’t very comfortable for me.

I did some searching and found a neat little adapter on the Pignology website. Unfortunately, at the current time, they aren’t accepting orders. A little more searching produced AG6QR ‘s article, which provided a perfectly workable solution. Best of all, I had everything I needed in my junk box.

Inspired by Rich’s article, I assembled a two-pin, female header connector (with standard 0.1-inch spacing) by crimping on a short length of two-conductor wire. On the other end, I soldered on an in-line 1/8-inch stereo jack. (I connected to the tip and sleeve terminals, leaving the ring terminal open.)

This is the 2-pin female header connector. It’s an Amphenol part but, unfortunately, I don’t have the specific part number.

After setting the CW KEY2 jack to the “HAND” setting, I connected my header connector to the two right-most pins on the front connector and a straight key to the stereo jack. Voila! It worked just fine. As is my usual practice, I used a little Goop sealant/adhesive to add a little extra strain relief and make the connectors more rugged for field use.

This is the straight key adapter connected to my KX3.

So until Pignology reopens, I have a great (cheap) solution for simultaneously connecting a straight key and paddles. Be sure to check out AG6QR’s page for a more detailed description (and better photography).

72, Craig WB3GCK

Quick End Insulator

Here’s another quick hack that took longer to write up than to actually build. I recently built a portable vertical antenna using some #26 Stealth Wire. I needed some sort of end insulator that would facilitate pruning the wire to resonance. Here’s my quick and dirty solution.

Using scissors, I cut a piece of plastic from a used up gift card I had in my wallet. The piece I cut is about 1 inch by 0.5 inches. Then, I drilled 3 holes in it. Two of the holes were just slightly larger than the #26 Stealth Wire (The Wireman Product #534). These holes hold the wire in place. I drilled a larger hole for attaching to a light line or, in my case, a small clip at the top of my telescopic pole. I also rounded off the corners a bit.

The end insulator and the gift card from which it was cut. (Disclaimer: I have no financial interest in the Wawa company, except that I have consumed untold quantities of their coffee over the years.)

So far, this is working out well for my portable vertical antenna. If I was using heavier gauge wire, I would definitely use something more substantial than the gift card. I also wouldn’t use it for a permanent installation. But for an ultralight antenna that is only used for portable excursions, it’s perfect.

If I ever need to replace it, I have enough of the original gift card left to make a bunch more!

72, Craig WB3GCK

Bike Rack Vertical

[This is an updated version of a post that appears on my old website. – WB3GCK]

I do quite a bit of my QRP operating from portable locations. I like to use simple wire antennas but, truth be told, I really dislike spending my limited operating time trying to get antenna wires up into trees. Also, when activating parks for Parks on the Air (POTA), I often operate from the cab of my truck and need an antenna that is self-contained and quick to deploy. This set up fits the bill.

What I did was modify my homebrew roll-on mast support so I could use my hitch-mounted bicycle rack to support it. This only required the drilling of two holes in the roll-on mount. Figure 1 shows the roll-on mount clamped into the bike rack. In this case, I was supporting a 31-foot Jackite pole. After extending the pole and removing the bottom cap, I just lower the pole onto the 1-1/4 inch pipe. That’s all there is to it.

Bike Rack Antenna Mount. A 9:1 unun is attached to the Jackite pole with a bungee cord.

By selecting the right size of pipe, I can use this technique to support a variety of masts. For example, I’ve used this type of mount to support two 5-foot sections of TV antenna mast. I used this configuration to support a 1.2 GHz yagi for DStar digital communications during an ARES-RACES drill years back.

My new truck's first QRP-portable outing. — The Bike Rack Vertical in use

When operating QRP-portable, I often use a vertical antenna made from a 30-foot piece of hook-up wire and fed through a homebrew 9:1 unun with an 18-foot length of RG-8x coax. The unun is just attached to the 31-foot Jackite pole using some small bungee cords. No radials are used, which gives this set-up virtually a zero footprint. You can find more information on this configuration on the EARCHI website. I’ve successfully used this antenna in the field over the past few years. It’s a bit of a compromise, as antennas go, but it has always served me well. The extra height using the bike rack mount seems to help performance a bit. (Although I can’t quantify that, I’m sure the extra height doesn’t hurt.) With the internal antenna tuner in my KX3, I can work all bands from 40 through 10 meters. Heck, I’ve even used it on 80 meters a bunch of times.

I used this particular antenna configuration countless times in recent years. It was my “go to” antenna for NPOTA activations. Within 5 minutes of arrival, I can be on the air. When it’s time to leave, tear down is just as fast. Now, that’s what I’m talkin’ about!

73, Craig WB3GCK

“Stationary-Mobile” with My 19-foot Vertical

Earlier this year, I built a lightweight, 19-foot vertical. Intended for tripod or ground mounting, I did the initial tuning and pruning of the vertical in that configuration. Today, I thought I’d see if it would work mounted on my pickup truck.

I have this plastic crate that I keep in the bed of the pickup truck. I use it to hold parts for my drive-on antenna mount, along with some tools and miscellaneous “stuff.” I hold the crate in place using bungee cords attached to a cargo bar that spans the width of the bed. I decided to make use of the crate as a quick and dirty antenna mount.

I took some 1-inch PVC pipe with a female threaded coupler from a previous antenna project and attached it to an inside corner of the crate with heavy-duty zip ties. I kept this part short enough to fit underneath the tonneau cover when traveling. To mount my 20-foot Black Widow pole, I used a 1-inch PVC male coupler and a reducer to go down to a 3/4-inch PVC pipe. The 3/4-inch PVC pipe fits nicely up inside the Black Widow pole. I went with the Black Widow pole rather than the lighter weight pole I normally use with this antenna since I already had all the PVC parts I needed to mount it.

My makeshift mount. The PVC mount is attached to the plastic crate, while the crate is attached to a cargo bar using bungee cords. The random junk I store in the crate keeps things stable.

I headed out to a local park today to give it a try. It only took a few minutes to get it set up. From the antenna, I ran some RG-8x coax through a window and into the cab of the truck. I connected the antenna ground to the body of the truck using a short piece of braid to a metal plate used to latch the tonneau cover closed.

The Black Widow pole installed on my makeshift mount.

I fired up my antenna analyzer and the SWR was off the charts. On closer inspection, I found the plate I was using for my ground wasn’t actually attached to the body of the truck. Instead, I connected two radials and ran them off the back of the truck. This time the SWR on 40 and 30 was much better. The resonant frequencies in this configuration were higher than when ground-mounted but my KX3’s internal tuner easily handled the minor mismatches.

I started out on 20 meters where this antenna operates as a random wire. I heard N5PHT doing a Parks on the Air (POTA) activation (KFF-3023) down in Texas. I gave him a call and exchanged reports. Moving down the band, I worked XE1XR in Mexico. So, the antenna seemed to be working fine. I checked 30 meters but it was devoid of activity.

Down on 40 meters, I had a nice ragchew with Bernard VE9BEL. Bernard was operating a club station (VE9CRM) in New Brunswick, Canada. He gave me a 599 and said I was “booming” into New Brunswick. Not bad for 5 watts into a 19-foot loaded vertical. I last worked Bernard a few years ago from Mt. Misery in Valley Forge National Park. We had strong signals both ways on that day, too.

So, it looks like this antenna is usable from the truck. I still need to find a way to connect the ground to the body of the truck. If possible, I’d like to avoid drilling holes in my new truck. This antenna is a little easier to deploy than my usual “Bike Rack Vertical.” The downside is I have to exit the truck to change bands. Life is a series of trade-offs, I guess.

73, Craig WB3GCK

The Quickie Whip

This week, my ham radio activity was focused on an emergency communications exercise with my local ARES-RACES group. I thought I’d do a post about the simple whip antenna I used with a dual-band radio. I cobbled this set up together a few years back and it has come in handy on several occasions.

During the exercise, I was operating indoors with easy access to our local repeaters. I was copying digital traffic using the Narrowband Emergency Messaging System (NBEMS), so a handheld radio wasn’t a good option. In this situation, a dual-band mobile radio and this little whip antenna hack were able to get the job done.

The Quickie Whip attached to my old Icom 207-H dual band radio

For the whip, I use commercially available, collapsible BNC whip antennas for the 2 meter and 440 bands. To connect the whip to the radio, I use a UHF-Male to BNC-Female right angle adapter I picked up on eBay. To help improve the efficiency, I attach two 1/4-wave counterpoise wires, one for 2 meters (about 19 inches) and one for 440 (about 6.3 inches).

Quickie Whip Antenna components: telescopic whip antenna, PL-259 to BNC-F right-angle adapter, and the modified 9V battery clip for the counterpoise wires.

To attach the counterpoise wires, I re-purposed a 9-volt battery holder. I just drilled out one of the mounting holes and used a small bolt and nut to attach the wires. The clip is just about the perfect size to snap onto the right angle adapter.

The antennas I use came from Smiley Antenna. I have 5/8-wave whips for 2 meters and 440, along with a halfwave whip for 2 meters. Although some of the antennas are specified to handle 50 watts, I generally use them only for 10 watts or less (in the interest of RF safety). If I need to run more power, I’ll go with an antenna placed a safe distance away.

I’ve used this simple antenna arrangement in several situations in recent years. It’s become a permanent part of my emergency communications go-kit.

73, Craig WB3GCK